In a printer, print characteristics, such as a position and a density of a printed image, is changed due to aging of each component associated with the use of the printer and due to a change in the environment, such as the temperature and the humidity. A calibration process is executed to prevent image quality from degradation caused by the change in the print characteristics. In the calibration process, a predetermined pattern is printed to detect deviations of printing positions and density levels by detecting the predetermined pattern by a sensor and the deviations are calibrated. The printer that executes the above calibration process is disclosed in Japanese Patent Application Publication No. 2002-296851.